Police Ombudsman Marie Anderson has described meeting the families of four innocent Catholics shot dead by the RUC more than 50 years ago as "emotional".
The ombudsman was speaking after her office released the long awaited report into the killings.
Schoolboy Patrick Rooney (9), the first child killed in the Troubles, Hugh McCabe (20), Samuel McLarnon (27), and 28-year-old Michael Lynch were all shot dead by the RUC in August 1969.
Ms Anderson described relatives, whom she met separately yesterday, as "dignified".
"I met with all of the families and I thought it was very emotional," she said.
"It was emotional for them and emotional for me.
"Because, I think they have waited for a long time and their grief has spanned decades now."
Some relatives of the dead have been told by prosecutors that no charges will be brought in relation to the killings.
Speaking to the Irish News last night, Ms Anderson said she shared the disappointment and frustration of relatives that there will be no prosecutions.
"Yes I do, I recognise and acknowledge their frustration," she said.
"I think it is legitimate frustration.
"I think they have been through this process of waiting for the Public Prosecution Service decision and then waiting for my report and while they remained frustrated, although its not for me to say, its for them to say how they felt about today, I think they were grateful for the answers and the finding in my report," she said
Ms Anderson said the central conclusion reached by her report relates to police failures.
"I think the most significant conclusion is - even allowing for the tumultuous circumstances of the time, the violence and the civil disorder, it has been described as close to civil war as you will get," she said.
"Even given all that it was the RUC failure to effectively investigate any of the deaths as soon as possible and at the time."
Asked if she has an expectation that the chief constable should apologise to the families of the dead Ms Anderson said: "It's a matter for the chief constable.
"My view is, I believe he should reflect on the contents of my report and consider whether in the circumstances an apology is appropriate."